Add support for file URIs and extracting the file path from file URIs

runtime/lib/uri_patch.dart

Index: runtime/lib/uri_patch.dart
diff --git a/runtime/bin/vmservice/service_request_router.dart b/runtime/lib/uri_patch.dart
similarity index 62%
copy from runtime/bin/vmservice/service_request_router.dart
copy to runtime/lib/uri_patch.dart
index 6bb5de542e97b7dc864a804db8a38dde9bb4a98f..84759eb123f478d56d4905fb76d147e21991ed52 100644
--- a/runtime/bin/vmservice/service_request_router.dart
+++ b/runtime/lib/uri_patch.dart
@@ -1,9 +1,9 @@
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+// Dart core library.
 
-part of vmservice;
-
-abstract class ServiceRequestRouter {
-  bool route(ServiceRequest request);
+// VM implementation of Uri.
+patch class Uri {
+  /* patch */ static bool get _isWindows native "Uri_isWindows";
 }